chore(deps-dev): bump vscode-extension-tester from 5.6.0 to 5.8.0

Bumps [vscode-extension-tester](https://github.com/redhat-developer/vscode-extension-tester) from 5.6.0 to 5.8.0.
- [Release notes](https://github.com/redhat-developer/vscode-extension-tester/releases)
- [Changelog](https://github.com/redhat-developer/vscode-extension-tester/blob/main/CHANGELOG.md)
- [Commits](redhat-developer/vscode-extension-tester@v5.6.0...v5.8.0)

---
updated-dependencies:
- dependency-name: vscode-extension-tester
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>